package com.tn.exam.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.tn.exam.constant.ExamConstant;

public class UserLoginFilter implements Filter{

	public void init(FilterConfig filterConfig) throws ServletException {
	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse resp = (HttpServletResponse) response;
		String actionName = req.getServletPath().substring(1);
		
		String username = (String) req.getSession().getAttribute(ExamConstant.SESSION_USER_KEY);
		if(username == null){
			if("login.action".equals(actionName)){
				chain.doFilter(request, response);
			}else{
				req.setAttribute("message", "请先登入再操作，谢谢-_-。");
				req.getRequestDispatcher("/login.jsp").forward(request, response);
			}
		}else{
			if("login.action".equals(actionName)){
				resp.sendRedirect(req.getContextPath() + "/index.action");
			}else{
				chain.doFilter(request, response);
			}
		}
	}

	public void destroy() {
	}

}
